Re: [CAD_CAM_EDM_DRO] PC ports, Encoder resolution and EDM PSU info

The article you speak of was written by C. R. Amsbury, and appeared in the
16 July 1976 (No. 3541) and concluded in the 6 August 1976 (No. 3542) issue
of Model Engineer. You are correct that a stepping motor was used, but no
PC board layout is given. A commercial PC board was used to drive the
motor. I built one, and used it successfully for a time, but it was very
slow. This was due to the very low amperage available from the power
supply. It operated at ~300 Volts. I eventually realized that this was a
lethal voltage to have exposed, and I dismantled the machine. The drive
mechanism was not well designed, and it developed rotational play. Amsbury
published an update in the 2 October 1981 issue of Model Engineer, with a
redesigned drive, and an operating voltage of ~40 Volts, but still no PC
board.

My bibliography of shop built EDMs includes the Strictly IC series starting
in the August/September 1993 issue and ending in the April/May 1994 issue.
Then there is the HSM "Build an EDM" series by Robert Langlois which was
published as a book by Village Press. Finally, Benjamin Fleming published a
small book describing a "Metal Disintegrator". I choose to ignore the
Popular (Mechanics/Science?) line voltage "tap busters" as being too
dangerous to consider.

Robert Grauman in Sunny Alberta

> Jon;
> some time ago in the Model engineering workshop magazine was a project

about a edm machine, and for what I can remember it used

> stepper motors for lifting the electrode up and down,everything was

described, power supply ,mechanics,and even the pcb was

> available.
> regards
> mariano